2015/07/28 by M. Posik, Posik, M.
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #Nuclear Experiment (nucl-ex) #hep-ex #nucl-ex
paper · pdf · doi:10.48550/arxiv.1507.07854
Submitted to DIS 2015 Proceedings. Corrected author heading
arxiv created 2015/07/29 · arxiv updated 2015/07/30
Over the past several years the STAR experiment at RHIC has been contributing to our understanding of the proton structure. Through its instrumentation, STAR is well equipped to measure W → ν+ e in √(s) = 500/510 GeV proton-proton collisions at mid-rapidity (-1.1 ≤ η≤ 1.1) . The W cross section ratio (W+/W-) is sensitive to unpolarized u, d, u, and d quark distributions. At these kinematics, STAR is able to measure the quark distributions near Bjorken-x values of 0.1. The RHIC runs in 2011, 2012 and 2013 at √(s) = 500/510 GeV saw a significant increase in delivered luminosity from previous years. This resulted in a total data sample being collected of about 352 pb-1 of integrated luminosity. The increased statistics will lead to a higher precision measurement of the W+/W- cross section ratio than was previously measured by STAR's 2009 run, as well as allow for a measurement of its η dependence at mid-rapidity. Presented here is an update of the W cross section ratio analysis from the STAR 2011, 2012 and 2013 runs.